The military and the police must train for situations that involve deadly force. One widely used training system is the Multiple Integrated Laser Engagement System (MILES) that equips each participant with vest containing a series of laser light detectors and suitable electronics. Participants use weapons that fire a laser beam along with a blank round. If a participant's detector is illuminated by a weapon's laser beam, the system provides a signal to the participant and a central command that he has been killed or wounded. MILES permits participants to conduct simulations using real weapons ranging from handguns to heavier weapons without subjecting the participants to the obvious danger of using real ammunition in those weapons.
One common military device that has been difficult for MILES to stimulate is the hand grenade. The typical MILES grenade cannot conveniently use a laser to signify a detonation because a grenade detonates in an unpredictable position after being propelled a distance from the user. Furthermore, a grenade is not directional like a bullet or a laser; it can kill or wound multiple people who are unprotected and within a “kill radius” distance of the grenade. Accordingly, the MILES grenade must be able to provide information upon detonation that each participant's receiver will use to determine if that participant is within the kill radius of a prototype grenade.
S. Sampson et. al., U.S. Pat. No. 6,579,097, discloses a MILES grenade that emits encoded infrared signals on detonation. The system tracks the location of each participant and the location of detonation of the grenade, and ‘kills’ participants within the fill radius of a detonating grenade.
R. Lynch et al., U.S. Pat. No. 6,569,011, discloses a paintball system where locations are tracked and participants within a predetermined distance of a simulated grenade are designated as ‘killed’.
C. Campagnuolo, SIR H1415, discloses a MILES system where the grenade makes a distinct noise and MILES bases damage to a participant on the amplitude of the received noise signal.
The U.S. Department of Energy, in an undated specification for MILES equipment, requires a MILES hand grenade to have an effective kill radius of up to 10 meters, an electronic output to interface directly with the MILES equipment, and an output signal that provides an indication to participants that the grenade exploded. An undated specification sheet by Schwartz Electro-optics Inc. shows a grenade simulator designed to those specifications. The Schwartz simulator is understood to generate an RF signal of sufficient strength to be detected only within the kill radius.
One difficulty with existing grenade simulators based on noise is that battlefield simulations are noisy environments, and a determination of distance based on amplitude of a received audio or electronic signal is not reliable. A difficulty with simulators using multiple laser outputs is possible eye damage to participants from the high output lasers used in some of these devices. A difficulty with grenades that rely on the intensity of an RF signal is that a hand grenade is activated after being thrown by a user, and it may land in any orientation. The uncertain position of the grenade antenna with respect to the receiver provides an uncertainty in the strength of the received signal.